when using
<%= Html.DropDownListFor(model => model.FeeTypeId, Model.GetFeeTypes(), new { })%>
in this case the right option is selected according to Model.FeeTypeId when the select is rendered.
BUT
if you render the form using a partial view, passing it a specific HtmlFieldPrefix (you will need it if,for example, you want to render two identical views and want different ids the elements)
<% Html.RenderPartial("path-to-partial-view", Model, new ViewDataDictionary() { TemplateInfo = new TemplateInfo() { HtmlFieldPrefix = "myPrefix" } }); %>
then the value will not be selected.
looks similar to the problem at DropDownListFor in EditorTemplate not selecting value but from different cause.
looked in the MVC 3 source and seems like the problem is at the SelectInternal method
it uses the htmlHelper.ViewData.Eval(fullName);
which fails to get the value by the full name when it contains the prefix,
TextBoxFor doesn't fail as it passes the value of the expression to InputHelper so it doesn't get to use the ViewData.Eval
just to be sure tested it at the partial view:
in the partial view the following will print "myPrefix.FeeTypeId"
<%= Html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName("FeeTypeId") %>
and the following will print "by property name: [value] by full name: [empty string]"
<%="by property name: " + Html.ViewData.Eval("FeeTypeId")%><br />
<%= "by full name: " + Html.ViewData.Eval(Html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName("FeeTypeId"))%>
The only solution i found is to generate a List at Model.GetFeeTypes() and mark the option i want as selected:
<%= Html.DropDownListFor(model => model.FeeTypeId, Model.GetFeeTypes(Model.FeeTypeId), new { })%>
don't really like this solution + i know i can create the List in the partial view which is also ugly,
is there another solution to this?
I have discovered that this is a bug in MVC. It's not fixed, though there is a work around.
See my question answered by myself (I had the same problem before finding your post).
MVC4 binding drop down list in a list (bug)
Regards
Craig
Related
Expanding on a previous question, I'm using EditorFor to edit a list of objects of type (let's say) Hobby.
Now, I need to implement functionality to add editors for individual Hobby objects, so that the user can add additional hobbies.
I read Steven Anderson's blog about how to do that in MVC 2. However, he's rendering the individual Hobby instances using a loop and RenderPartial, rather than using EditorFor. I understand his approach of making Ajax calls to render another partial view and inserting the view result into the DOM, but don't know how to apply the Ajax add in my case, with EditorFor.
His code:
<% foreach (var item in Model)
Html.RenderPartial("GiftEditorRow", item);
%>
My code is using EditorFor like this:
// Model is a List<Hobby>
#Html.EditorFor(model => model.AllowedSurveys)
How do I add an additional Hobby editor, given that the editor is implemented as an Editor Template rather than as a Partial View?
You could replace your editor template with a partial:
#foreach (var item in Model.AllowedSurveys)
{
Html.RenderPartial("_Hobby", item);
}
and inside the partial (~/Views/controllerName/_Hobby.cshtml):
#model Hobby
<div class="editorRow">
#using(Html.BeginCollectionItem("AllowedSurveys"))
{
#Html.EditorFor(x => x.Name)
...
}
</div>
The Html.BeginCollectionItem custom helper is used to generate names with Guids and allow for reordering and adding new items to the collection using javascript. You can download it from the updated article. The one you were reading was for ASP.NET MVC 1 and is obsolete.
I've been able to correctly display a dictionary as a dropdownlist as well as pull it's value on a page submit. But on the GET (initial display) the selected item does not reflect the object's value. My controller is passing state:
ViewData["Status"] = new SelectList(AppHelper.WebinarStatuses, "Key", "Value", selectedStatus);
the View:
<%: Html.DropDownListFor(m => m.Status, (ViewData["Status"] as SelectList), Model.Status )%>
I understand that I need to find the right overload of the DropDownListFor helper - I don't understand how I go about doing that. Small picture, what syntax forces the select list to display what the controller's sending - bigger picture, how do I discover/interpret which overload does what?
profuse thanks
I'm not sure how to phrase this one but here goes nothing.
I have a controller that has two parameters: FindingId, TagId
public JsonResult Add(int FindingId, int TagId)
I have an Ajax ActionLink to call it:
<%: Ajax.ActionLink( "Add", "Add", "FindingTag",
new { FindingId = Model.FindingId },
new AjaxOptions {
HttpMethod = "Post"
})
%>
I then have a dropdownlist of available Tags:
<%: Html.DropDownListFor(m => m, Model.AvailableTags, "Select Option..", new { id = "finding_" + Model.FindingId + "_AvailableTags" } )%>
The parameters are populated in the following way:
You can see above that I am filling in the FindingId when the model is being rendered since that will always be the same in this subsection. This view is being rendered multiple times for different Findings so that FindingId will change per model.
The TagId however should come from the selected value of the DropDownList.
I am not mapping this particular request to a viewmodel to pass in so the dropdownlist is not being bound to a particular property. I have also created a route for
/FindingTag/Add/{FindingId}/{TagId}
So here are the questions this has opened and I'm really hoping someone can help me out as this stuff is really knew to me.
1) I found that the href is being rendered as Add?FindingId=## and I was curious if I can force that to render to Add/##
2) Is there an easier way I can get the value from the dropdownlist to append to the href to create the route mentioned above?
Most of the time in the project I have been using jQuery for my ajax calls so I would just manually build a URL from scratch, but I was really hoping to use the MS versions for practice. Does this seem irrational? Let me know if you have any suggestions or insight..
Edit:
I am not sure if this is the way to go about this. I am finding people saying to use a form and submit that, but if I have this as a subsection of an already strongly-typed partial view, how do I get the values to be sent back in a form I can use that isn't the fullfledged model? I would prefer to keep it to the 2 parameters and not a complex object if possible.
This code was converted from some ASP.Net MVC 2 code in this tutorial:
MVC 2 Editor Template with DateTime
It is a custom EditorTemplate for DateTime fields stored as 'EditorTemplates/DateTime.cshtml'.
#Model DateTime?
#Html.TextBox("", (Model.HasValue ? Model.Value.ToShortDateString() : string.Empty), new { #class = "datePicker" })
However I get the following error when using #Html.EditorFor(model => model.NewAbsence.StartDate):
CS1973: 'System.Web.Mvc.HtmlHelper' has no applicable method named 'TextBox' but appears to have an extension method by that name. Extension methods cannot be dynamically dispatched. Consider casting the dynamic arguments or calling the extension method without the extension method syntax.
I've seen some similar posts on here which mention casting the parameter of the EditorFor method, however I cannot seem to get this to work in my example.
Could someone please point out what I will need to change in my code. Thanks.
Actually it's #model with lowercase m:
#model DateTime?
^
instead of:
#Model DateTime?
So to sort of summarize what people are saying, and make it a bit more generic. If your view is declaring that it accepts dynamic models:
#model dynamic
Then things like extension methods will not be able to infer the types of arguments passed to them. Here are two examples (using Razor because it's awesome):
#Html.TextBox("myTextBoxName", Model.MyTextBoxValue)
#Html.DropDownList("myDropDownName", Model.MySelectList))
In these cases, the engine doesn't know what types Model.MyTextBoxValue or Model.MySelectList are, therefore it can't figure out what overloads of the extension methods to compile. So you just help it along with some strong typing:
#Html.TextBox("myTextBoxName", (string)Model.MyTextBoxValue)
#Html.DropDownList("myDropDownName", (SelectList)Model.MySelectList))
By the way, just to stop people from potentially pulling out their hair, that SelectList has to be properly instantiated with something like:
var items = List<SelectListItem>();
...
new SelectList(items, "Value", "Text");
As a temporary work around I am using:
<div class="editor-field date-field">
#Html.EditorFor(model => model.NewAbsence.StartDate)
#Html.ValidationMessageFor(model => model.NewAbsence.StartDate)
</div>
Then using the jQuery selector:
$(".date-field > input").datepicker({
showOn: "button",
buttonImage: "*pathtoimage*"
});
To apply the date picker to the input tags within the 'date-field' div. However this still doesn't format the date value how I want it to display initially, and cuts out the editor template entirely.
The error message comes from your textbox statement. In a template, this becomes a dynamic expression, and .Net doesn't know how to type the Model properties.
#Html.TextBox("", (string)(Model==null ? Model.Value.ToShortDateString() : string.Empty), new { style = "width: 10em;", #class="datefield" })
Explicitly cast your date value as string, and the dynamic expression has the information it needs. I also had a problem with the .HasValue property, but that wasn't the point of your question.
i have been playing around with MVC. I am currently stumped on with html helper methods. One thing i have noticed is that I cant really cant apply the ASP.NET Web Form logic into MVC. To explain further, in ASP.NET I could create a Label control and assign it some text data and then read the text data.
However, in MVC, I cant seem to do the same with #Html.LabelFor/#Html.Label, I have realised that once you do a POST from your form, the value from the Label is not bound back into my view model. However, if I use an EditorFor or TextBoxFor, I can get values bound to my viewmodel upon POST.
My question what html hlper method should I use to display text as readonly but yet be able to bind back to my viewmodel upon post ? I have tried TextBoxFor with its html attributes set to disabled and readonly but no luck.
Appreciate any pointers.
thanks
You should be able to bind the readonly attribute to the TextBox by passing in htmlAttributes as the 2nd parameter of the TextBoxFor method:
<%=Html.TextBoxFor(m => m.SomeProperty, new { #readonly = "readonly" }) %>
On MSDN: InputExtensions.TextBoxFor Method (HtmlHelper, Expression>, Object)
If you're trying to maintain the Label value you can use a combination of the LabelFor and HiddenFor methods.
I don't know why you would need to do this though, since you should be able to get the DisplayText attribute or the Property Name from the property.
<%=Html.LabelFor(m => m.SomeProperty) %>
<%=Html.HiddenFor(m => m.SomeProperty) %>
but this doesn't make a lot of sense since the usual syntax would be:
<%=Html.LabelFor(m => m.SomeProperty) %>
<%=Html.TextBoxFor(m => m.SomeProperty) %>
Note that if you use the disabled attribute the input will not be posted when the form is submitted
This is expected behaviour, only values form elements are added to your Model on POST so your label will be ignored. To get around this duplicate your label value in a hidden field
Html.HiddenFor(model => model.FieldName)
or
Html.Hidden("FieldName", model.FieldName)